Could we see a photo?

Custom made?

Are there some photos provided here? I personally recommend this custom site. They look great!!! I'm going to have some of their blackout styles!

https://www.nicetown.com/?gclid=Cj0KCQjwgMqSBhDCARIsAIIVN1VR5Y8vt4nSby_y-k1ENiXdHoKUhg136AN-tBURpGfDhDd9qHcGh7caAmI6EALw_wcB

The curtains do not have to exactly match the trim color. Just how far off are they? It's difficult to determine the actual color from photos on a computer monitor.

If you are wanting ready-made curtains, try Ikea, Pottery Barn and The Vermont Country Store. You can order a sample or several small curtains (usually a valance), and compare to select the one you like best. They have lots of white curtains in lots of fabrics. If you want custom, then your fabricator or designer should be able to provide fabric samples to allow you to select the one that works best with the trim.

I've used off-white IKEA and Target curtains. But hard to tell without seeing photos of your trim/curtains.

Are the present curtains lined? If any natural light coming through the fabric will alter the color. And any painted wall behind it will alter the color.

A bit more expensive, but the one thing (the onyl thing) I recommend from Restoration Hardware is the line of Perennial fabrics for draperies.

I think we need pics and info I do not usually like white drapes thay often look like sheets and I use the bedding to drive the decor in a bedroom so post some pics if you really want actual help.